The ship could not withstand the 80 to 90 mph winds with 7- to 9-foot waves on Tuesday afternoon that ultimately caused the ship to flip over.

“We are hopeful. We can’t do this work if you’re not optimistic, if you’re not hopeful,” Coast Guard Captain Will Watson of the New Orleans Sector said at a press conference on Wednesday about those missing, AP reported.

One crew member was found dead, while six of the 12 others were found alive.

The winds that affected the Seacor Power could be qualified as Category 1 hurricane winds, according to the Saffir-Simpson Hurricane Wind Scale.

The Coast Guard received an emergency signal around 4:30 p.m. on Tuesday, prompting the response.

Newsweek reached out to the U.S. Coast Guard for further comment but did not hear back in time for publication.

For more reporting from the Associated Press, see below.

The bulky vessel with three long legs that can be lowered to the sea floor to make it an offshore platform flipped over Tuesday afternoon miles south of Port Fourchon. At one point, video showed the massive ship with one leg pointed awkwardly skyward as rescuers searched the heaving water.

Lafourche Parish President Archie Chaisson III said time is critical in the rescue effort because “we have the potential for some rough weather around lunchtime.”

“The hope is that we can bring the other 12 home alive,” Chaisson said.

The search involved at least four Coast Guard vessels, four private ones and Coast Guard airplanes based in Corpus Christi, Texas, and Mobile, Alabama. A Coast Guard helicopter also was being used.

Relatives of the missing crew members rushed to the port from their homes nearby, seeking any information they could get, Chaisson said.

“We continue to pray for the…men who were on that vessel as well as their families,” Chaisson said.

The company that owns the ship, Houston-based Seacor Marine, set up a private hotline to share information with families of those onboard, Chaisson said. An employee who answered the phone Wednesday morning said he had no immediate information he could share.

The National Weather Service in New Orleans had advised of bad weather offshore, including a special marine warning issued before 4 p.m. Tuesday that predicted steep waves and winds greater than 50 knots (58 mph).

An emergency distress signal prompted multiple private vessels in the area to respond, saving four crew members, the agency said. Coast Guard crews rescued another two people.

Although the Coast Guard said the lift boat capsized during a microburst, a National Weather Service meteorologist said the system was more like an offshore derecho.

“This was not a microburst—just a broad straight-line wind event that swept over a huge area,” Phil Grigsby said.

He said the weather service’s nearest official gauge, at Grand Isle, showed about 30 minutes of 75 mph (120 km/h) winds, followed by hours of winds over 50 mph (80 km/h).

The initial storm system was followed by a low-pressure system called a wake low, which amplified the winds and made them last longer, Grigsby said. “It was the strongest wake low I’ve seen in almost 18 years here,” he said.

Captain Ronald Dufrene said his offshore trawler, Mister Jug, was among the shrimp boats that struggled to survive.

“People who have been fishing 30, 40 years—the first time they put their life jackets on was yesterday….I know three boats for sure said that,” Dufrene said.

He said the captain who was on board his boat told him seas rose 15 to 20 feet (5 to 6 meters) and the wind gauge was lost at 80 mph (129 km/h), but a crewman told him later that he saw the gauge at 95 mph, “then the wind laid the pole over.”

The 95-mph (153 km/h) report can’t be taken as official, Grigsby said. “We don’t know how well-calibrated their instrument is. But it’s not outside the realm of probability,” he said.

Port Fourchon, Louisiana’s southernmost seaport, is a major base for the U.S. oil and gas industry, supporting most of Louisiana’s offshore platforms and drilling rigs.

The storm also overturned other vessels and damaged property from Louisiana’s shore up to New Orleans.

“Please join @FirstLadyOfLA and me in praying for those who remain missing after yesterday’s capsizing off the coast of Grand Isle and for those who are working to rescue them,” Louisiana Governor John Bel Edwards said Wednesday on Twitter.